Indexing chuck

An indexing chuck (1)

• comprising a chuck body (2) in which an accommodating opening (3) with a ring-shaped design is worked into the chuck body (2) and runs centrally in relation to its longitudinal axis (4),
• comprising a pivoting ring (5) inserted in the accommodating opening (3) of the chuck body (2), on which pivoting ring (5) at least three clamping jaws (6) that can be advanced radially perpendicularly to the longitudinal axis (4) of the chuck body (2) are supported, by means of which a rotationally symmetrical workpiece (7) to be machined is locked in the chuck body (2) centrally in relation to its longitudinal axis (4),
• comprising an advancing device (8) which is inserted into the pivoting ring (5) and by means of which the clamping jaws (6) can be moved synchronously,
• comprising two pivot pins (11, 12) which are supported in the chuck body (2) and which form a pivot axis (13) and are in a non-positive or positive active connection with the pivoting ring (5) and
• comprising at least one driving means in a driving connection with one of the pivot pins,
• wherein the advancing device of the at least three clamping jaws is formed by a synchronising ring which is supported so as to be movable parallel to the longitudinal axis of the chuck body in the pivoting ring, a driving surface extending at an angle to the longitudinal axis of the chuck body is fastened to the synchronising ring in the region of the respective clamping jaw, and a contact surface is provided on the respective clamping jaw, which contact surface interacts with the driving surface of the synchronising ring in such a way that the clamping jaws are moved radially out of the pivoting ring
• characterised in that
• the clamping axes (6′) of the clamping jaws (6) run offset to the pivot axis (13) formed by the pivot pins (11, 12), that the advancing device (8) of the at least three clamping jaws (6) is formed by a synchronising ring (33) which is supported so as to be movable parallel to the longitudinal axis (4) of the chuck body (2) in the pivoting ring (5), that a driving surface (36) extending at an angle to the longitudinal axis (4) of the chuck body (2) is worked onto the synchronising ring (33) in the region of the respective clamping jaw (6), and that a contact surface (37) is provided on the respective clamping jaw (6), which contact surface (37) interacts with the driving surface (36) of the synchronising ring (33) in such a way that the clamping jaws (6) are moved radially out of the pivoting ring (5).